This file is a list of programs that can be configured in HTML Preferences as the associated applications for editing HTML files output by Tinderbox. The file is a list of application names and their macOS 'creator' strings.
Thus, to add a new HTML Editor/Viewer as a 'helper' you need to know its macOS 'creator' string and decide on the text you want for the on-screen name. The files will look something like this (without the XML comment):
<helper>
<!-- a list of helpers -->
<helper name="Firefox" signature="MOZB" />
</helpers>
The second line above defines 'Firefox' as a helper and this is the name you see in pop-up lists on the program. Under the hood, the creator type of 'MOZB' is passed to the macOS. It shows the syntax of the line you should follow when adding new helpers. In the following example, the Mac Browser Camino is added as a new helper, by inserting a new 'helper name' XML entity anywhere inside the
tags. The helper apps are listed in HTML preferences the order used in the file:
<helpers>
<helper name="Firefox" signature="MOZB" />
<helper name="Camino" signature="MOZC" />
</helpers>
The order in which the 'helper name' entities are listed in the XML is the order in which the helpers are listed in Tinderbox's helper pop-ups.
The application should be re-started after editing these files to ensure changes are detected.